Golf balls

Abstract

Disclosed herein are golf balls having a thermoplastic outer cover layer formed from a thermoplastic polyurethane composition. The golf balls are produced without the use of a secondary treatment step that would result in the crosslinking of the polyurethane cover composition.

1 . A golf ball consisting essentially of:
 a thermoset rubber core formed from a diene rubber composition and having a diameter of from 1.530 inches to 1.580 inches, a center Shore C hardness of from 60 to 70, an outer surface Shore C hardness of from 75 to 85, and a positive hardness gradient wherein the difference between the Shore C hardness of the outer surface of the core and the Shore C hardness of the center of the core is from 10 to 20;   a thermoplastic intermediate layer formed from an ionomer blend composition and having a thickness of from 0.020 inches to 0.040 inches and an outer surface Shore D hardness of greater than 65;   a thermoplastic outer cover layer formed from a thermoplastic polyurethane having a material hardness of from 48 to 55 Shore D and having a thickness of from 0.030 inches to 0.040 inches;   an optional adhesive coating disposed between the intermediate layer and the outer cover layer; and   one or more coatings disposed about the outer cover layer;   wherein the ratio of the molecular weight of the thermoplastic polyurethane composition prior to molding the outer cover layer to the molecular weight of the thermoplastic polyurethane composition after molding the outer cover layer is from 3 to 50; and   wherein the golf ball has a plurality of dimples on the spherical outer surface thereof, wherein the plurality of dimples are arranged in eight triangular dimple sections that are defined by projecting the eight faces of a square dipyramid onto the spherical outer surface of the ball, the eight triangular dimple sections being substantially identical in size and dimple arrangement.   
     
     
         2 . The golf ball of  claim 1 , wherein the golf ball includes a waterborne primer coating and a solventborne top coating. 
     
     
         3 . The golf ball of  claim 1 , wherein the dimple arrangement within each of the eight triangular sections is not rotationally symmetric about the center of the section; and wherein from 2% to 10% of the dimples have an elliptical plan shape. 
     
     
         4 - 6 . (canceled)